In modern internal combustion engines, devices for the variable adjustment of the control times of gas exchange valves are used to be able to vary the phase relation between the crankshaft and camshaft in a defined angle range between a maximum advanced position and a maximum retarded position. The device is integrated in a drive train by means of which torque is transmitted from the crankshaft to the camshaft. This drive train can be realized, for example, as a belt, chain, or gearwheel drive. In addition, the device is locked in rotation with a camshaft and has one or more pressure chambers by means of which the phase relation between the crankshaft and the camshaft can be varied selectively.
Such a device is known, for example, from DE 10 2007 041 552 A1. The device has a cell wheel, an impeller, and two side covers, wherein the cell wheel is in driven connection with a crankshaft and the impeller is locked in rotation on a camshaft. Here, the impeller is arranged so that it can pivot relative to the cell wheel in a defined angle interval. The side covers are arranged on the axial side surfaces of the impeller and the cell wheel and locked in rotation with the cell wheel by means of screws. The impeller includes an essentially cylindrical hub element and several separate vanes. The vanes are arranged in vane grooves that are constructed on the cylindrical outer lateral surface of the hub element and extend outward in the radial direction. In the hub element there are several hollow spaces that extend in the axial direction and are open on both axial side surfaces of the hub element.
The cell wheel, the impeller, and the side covers bound several pressure spaces. Each of the pressure spaces is divided by one of the vanes into pressure chambers that act against each other and form a hydraulic adjustment drive by means of which the phase position between the impeller and the cell wheel can be varied. The pressurized medium supply to and the pressurized medium discharge from the pressure chambers is realized via pressurized medium channels formed in the hub element. The pressurized medium channels communicate on one side with a central opening of the impeller and on the other side with the pressure chambers. The pressurized medium channels are constructed as boreholes that are formed in the hub element after the shaping process of the hub element.
Another device is known from U.S. Pat. No. 5,836,277 A. In this embodiment, pressurized medium channels are constructed as radial grooves on the axial side surfaces of the impeller.
Another device is known from DE 101 34 320 A1. In this embodiment, the vanes are formed integrally with the hub element. The integrally formed impeller is made from a plastic.
The present invention is based on the objective of specifying a cost-optimized and weight-optimized impeller of a device for the variable adjustment of the control times of gas exchange valves of an internal combustion engine.